Pathogenic mechanisms involving the interplay between adipose tissue and auto-antibodies in rheumatoid arthritis

We aimed to evaluate the association between adipose tissue (AT) dysfunction, autoimmunity, and disease activity in rheumatoid arthritis (RA). A cross-sectional study including 150 RA patients and 50 healthy donors and longitudinal study with 122 RA patients treated with anti-tumor necrosis factor (TNF)-α, anti-interleukin 6 receptor (IL6R) or anti-CD20 therapies for 6 months were carried out. In vitro experiments with human AT and adipocyte and macrophage cell lines were performed. A collagen-induced arthritis mouse model was developed. The insulin resistance and the altered adipocytokine profile were associated with disease activity, the presence of anti-citrullinated proteins anti-bodies (ACPAs), and worse response to therapy in RA. AT in the context of arthritis is characterized by an inflammatory state alongside the infiltration of macrophages and B/plasmatic cells, where ACPAs can have a direct impact, inducing inflammation and insulin resistance in macrophages and promoting a defective adipocyte differentiation, partially restored by biologicals.